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authorRussell King <rmk+kernel@arm.linux.org.uk>2015-05-15 11:02:23 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2015-05-15 11:06:35 +0100
commit1b97937246d8b97c0760d16d8992c7937bdf5e6a (patch)
treec1a283d279d553bf0b1b975ee280efe202e0087a /arch/arm/kernel/entry-common.S
parent965278dcb8ab0b1f666cc47937933c4be4aea48d (diff)
downloadlinux-linaro-stable-1b97937246d8b97c0760d16d8992c7937bdf5e6a.tar.gz
ARM: fix missing syscall trace exit
Josh Stone reports: I've discovered a case where both arm and arm64 will miss a ptrace syscall-exit that they should report. If the syscall is entered without TIF_SYSCALL_TRACE set, then it goes on the fast path. It's then possible to have TIF_SYSCALL_TRACE added in the middle of the syscall, but ret_fast_syscall doesn't check this flag again. Fix this by always checking for a syscall trace in the fast exit path. Reported-by: Josh Stone <jistone@redhat.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/entry-common.S')
-rw-r--r--arch/arm/kernel/entry-common.S4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index f8ccc21fa032..4e7f40c577e6 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -33,7 +33,9 @@ ret_fast_syscall:
UNWIND(.fnstart )
UNWIND(.cantunwind )
disable_irq @ disable interrupts
- ldr r1, [tsk, #TI_FLAGS]
+ ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
+ tst r1, #_TIF_SYSCALL_WORK
+ bne __sys_trace_return
tst r1, #_TIF_WORK_MASK
bne fast_work_pending
asm_trace_hardirqs_on